1. Technical Field
The present invention relates to a thin film transistor and a display device including the same, and more particularly, to a thin film transistor using a carbon nanotube as a channel and a display device including the same.
2. Discussion of the Related Art
Since the discovery of a carbon nanotube, the carbon nanotube has been researched for use in various fields. Particularly, after a transistor using the carbon nanotube having a semiconductor property was fabricated, additional studies related to its fabrication were performed. Further, as techniques for assembling the carbon nanotube into a desired structure were advanced, carbon nanotube transistors having various structures were developed. Since the carbon nanotube transistors may have very small sizes and be formed in a flexible substrate, new application possibilities have arisen. Further, by purifying only a carbon nanotube having a semiconductor property, a purified carbon nanotube with an improved semiconductor property has been developed, thereby opening the door to more applications.
However, conventional carbon nanotube transistors may operate normally only at a low drain-source voltage of about several volts. In other words, the conventional carbon nanotube transistors do not operate normally when the drain-source voltage is very large. This is because a Schottky barrier generated between the carbon nanotube and an electrode becomes a lot thinner when an applied voltage is very large and, as a result, a Schottky barrier modulation according to a gate voltage becomes negligibly smaller. Accordingly, when a high drain-source voltage is applied, a voltage ratio between on/off states becomes much smaller than that of when the low drain-source voltage is applied. In other words, the semiconductor property of the carbon nanotube may become weak. Therefore, the conventional carbon nanotube transistors are generally limited to low drain-source voltage applications.